Guideline Concordance with Durvalumab in Unresectable Stage III Non-Small Cell Lung Cancer: A Single Center Veterans Hospital Experience
Background: Durvalumab is recommended by national guidelines for patients with unresectable stage III non-small cell lung cancer (NSCLC) following concurrent chemoradiation therapy (CRT). Nonadherence to guidelines is associated with adverse outcomes. We studied the adherence and identified barriers to durvalumab usage at the Birmingham Veterans Affairs Medical Center (VAMC) Oncology Clinic in Alabama.
Methods: Using retrospective analysis, we assessed the use of consolidative durvalumab among veterans at Birmingham VAMC. The health records of all veterans with stage III unresectable NSCLC from October 2017 to August 2019 were reviewed. Data collected included demographics, barriers to CRT initiation and completion, durvalumab usage, and reasons for not prescribing durvalumab.
Results: In our data review, 34 patients were found to have stage III unresectable NSCLC. Twenty (58.8%) of those 34 initiated CRT, but only 16 (47.1%) completed CRT treatment and 7 (20.6%) underwent further treatment with durvalumab. Of the 14 patients who did not initiate CRT, the most common reasons were poor performance status and/or the presence of comorbidities. Of the evaluable cohort of 34, 11 (32.4%) patients with stage III NSCLC received durvalumab. Of the 9 eligible patients who did not receive durvalumab, the most common reasons cited were toxicities experienced during or following CRT (11.8%).
Conclusions: Just one-third of patients were eligible to receive durvalumab at Birmingham VAMC. This was likely due to the difference between clinical trial and real-world patient populations. Interventions to address socioeconomic and system level barriers to improve our center’s delivery of lung cancer treatment are planned.
Limitations
Study limitations included the biased and confounding factors previously described about retrospective and nonrandomized observational studies that are controlled for during RCTs.15 Electronic health record data may have been incorrectly collected resulting in missing or wrong data points that affect the validity of our conclusion. Recall bias with regard to documentation by health care providers describing reasons why CRT or durvalumab were not initiated or the patient’s ability to recall previous treatments and report ECOG status or toxicities also may have impacted our findings. Comorbidities and poor performance status, frequently occurring among veterans, negatively impact cancer treatment decisions and may result in a detection bias. For example, tobacco use, cardiovascular disease, including heart failure, and chronic obstructive pulmonary disease, are notoriously higher in the US veteran population when compared with civilian cohorts.16-18 Also, veterans with poorly controlled depression and posttraumatic stress disorder resulting in functional impairment are a factor.19 Steps were taken to address some of these biases by performing repeat checks of tabulated data and employing 2 independent reviewers to evaluate all relevant clinical documentation, compare results, and reach a consensus.
Conlcusions
This retrospective analysis of adherence to category 1 NCCN guidelines for durvalumab use among patients at the Birmingham VAMC Oncology Clinic reinforced our practice and identified minor deficiencies in documentation that would impact future clinical visits. More importantly, it depicted the massive disparity in treatment candidacy among Birmingham veterans compared with clinical trial populations. Efforts will be made to address factors impacting a veteran’s candidacy for CRT and explore other variables such as socioeconomic barriers to treatment. Multiple complementary tools to assess patients’ frailty, such as the Charlson Comorbidity Index (CCI), are now being used for a variety of disorders including cancers. More robust data and standardization are needed to validate the use of these assessments in predicting response to immune checkpoint inhibitors.
Immune checkpoint inhibitors are currently being evaluated in stage III NSCLC studies and may be implemented as routine practice in the future.12 It is important to distinguish fit from frail veterans with lung cancer for treatment selection. We would like to see the expansion of the eligibility criteria for clinical trials to include patients with a performance status of ECOG 2 in order for results to be truly generalizable to the real-world population. Our hope is that such work will improve not only the quality of lung cancer care, but also the quality of care across multiple tumor types.
